Fluid handling devices are becoming increasingly popular and there is an increased demand for fluid handling devices which are both portable and easy to use. Portable fluid handling devices are being used for applications such as home care, point of care testing, fuel cells, fragrance dispensers, etc. In order for a portable fluid handling device to be effective and efficient, it must be light weight, small in size, consume minimal power, and be cost effective to manufacture. In many applications, it is also important that the fluid handling device provide an accurate and consistent fluid distribution. Therefore, it is necessary to incorporate an efficient fluid valve in the fluid handling device. In many aspects, the fluid valve characterizes the device's efficiency.
One solution of a portable valve that attempts to meet the above criteria is a miniature solenoid valve. The miniature solenoid valve however, is not as effective as originally anticipated. Solenoid valves however, are limited in both size as well as power consumption. In order to obtain adequate performance, a solenoid valve typically consumes a substantial amount of power. The power consumption of a solenoid valve, in some circumstances, is unacceptable when using batteries as a power source.
Another solution has been the use of electrically actuated piezo valves. Some piezo valves operate using a closing arm that seals against a sealing shoulder when the piezo element is de-activated. These valves typically require a substantial amount of space to operate and may not always provide an adequate solution as they are subject to clogging when used with liquids that may dry around the orifice. However, it is also known in the art to provide a sealing ball, which seals against a sealing shoulder.
For example, U.S. Pat. No. 6,142,394 discloses a fuel injector that uses a ball and pin valve. A piezo stack is in contact with a valve pin. Once the piezo stack is activated, the valve pin pushes a ball between a first and second seat thereby sealing against the second seat. The problem with this solution is that it relies on the valve pin operating correctly and maintaining contact with the ball. Furthermore, this solution faces the same challenges with clogging as piezo valves with closing arms.
U.S. Pat. No. 4,000,852 provides a similar solution. The '852 patent discloses a piezo valve with a ball sealing element held against a valve shoulder using a biasing device such as a spring. In this case, the piezo element is vibrated in an attempt to overcome the force of the spring and vibrate the ball away from the valve shoulder, thus, opening a fluid passage. However, the vibration created by the piezo element vibrates the entire valve, which requires excessive power consumption because a substantial amount of the vibration is dissipated throughout the valve. Additionally, the vibration must be great enough to overcome both the biasing device and the pressure provided by the incoming fluid.
FR 2,264,191 attempts to improve upon the '852 patent by removing the biasing device. Therefore, the fluid pressure holds the ball against the valve shoulder when the valve is deactivated. However, like the '852 patent, the piezo element acts on the entire valve, which can consume an unnecessarily high amount of power.
There is a need in the art to provide an electrically actuated valve that consumes a minimum amount of power and requires no power when deactivated. The present invention overcomes these and other problems and an advance in the art is achieved.
Aspects
In one aspect of the invention, a valve (100) including a housing (101) with fluid inlet (102) and a fluid outlet (205), the valve (100) comprising:                a vibrating element (206) adapted to vibrate when energized;        an amplifying plate (207) coupled to the vibrating element (206), the amplifying plate (207) including a fluid passage (208) providing fluid 25 communication between the fluid inlet (102) and the fluid outlet (205);        and        a sealing ball (209) located between the fluid inlet (102) and the amplifying plate (207), the sealing ball (209) adapted to seal the fluid passage (208).        
Preferably, the vibrating element comprises a piezoelectric material.
Preferably, the vibrating element comprises a piezoelectric ceramic.
Preferably, the valve further comprises an electrode adapted to electrically couple a power source to the vibrating element.
Preferably, the sealing ball seals the fluid passage when the vibrating element is not energized.
Preferably, the fluid inlet is adapted to receive a pressurized fluid and the pressurized fluid retains the sealing ball against the fluid passage when the vibrating element is not energized.
Preferably, the amplifying plate comprises a metallic plate.
Preferably, the amplifying plate amplifies a vibration produced by the vibrating element.
Preferably, the valve further comprises a sealing member coupled to the amplifying plate and adapted to prevent the fluid flowing through the valve from contacting the vibrating element.
In one aspect of the invention, a method of forming a valve including a housing having a fluid inlet and a fluid outlet, comprising the steps of:                positioning a vibrating element in the valve housing, the vibrating element adapted to vibrate when energized;        coupling an amplifying plate to the vibrating element, the amplifying plate including a fluid passage providing fluid communication between the fluid inlet and the fluid outlet; and        placing a sealing ball between the fluid inlet and the amplifying plate such that the sealing ball can seal the fluid passage.        
Preferably, the vibrating element comprises a piezoelectric material.
Preferably, the vibrating element comprises a piezoelectric ceramic.
Preferably, the method further comprises the step of coupling an electrode to the vibrating element and to a power source.
Preferably, the sealing ball seals the fluid passage when the vibrating element is not energized.
Preferably, the fluid inlet is adapted to receive a pressurized fluid and the pressurized fluid retains the sealing ball against the fluid passage when the vibrating element is not energized.
Preferably, the amplifying plate comprises a metallic plate.
Preferably, the method further comprises the step of coupling the amplifying plate to the vibrating element such that the amplifying plate amplifies a vibration produced by the vibrating element.
Preferably, the method further comprises the step of coupling a sealing member to the amplifying plate such that a fluid flowing through the valve is prevented from contacting the vibrating element.
In one aspect of the invention, a method of controlling a fluid flow using a valve including a housing with a fluid inlet and a fluid outlet:                the valve comprising:                    a vibrating element adapted to vibrate when energized;            an amplifying plate coupled to the vibrating element, the amplifying plate including a fluid passage providing fluid communication between the fluid inlet and the fluid outlet; and            a sealing ball located between the fluid inlet and the amplifying plate, the sealing ball adapted to seal the fluid passage;                        the method comprising the steps of:                    coupling the fluid inlet to a pressurized fluid source such that the pressurized fluid retains the sealing ball against the fluid passage; and            energizing the vibrating element sufficiently to overcome the pressure applied on the sealing ball, thereby unsealing the fluid passage.                        
Preferably, the vibrating element comprises a piezoelectric material.
Preferably, the vibrating element comprises a piezoelectric ceramic.
Preferably, the amplifying plate comprises a metallic plate.
Preferably, the step of energizing the vibrating element further comprises the step of energizing the vibrating element at a resonant frequency of the system.
Preferably, the method further comprises the step of de-energizing the vibrating element, wherein the pressurized fluid again retains the sealing ball against the fluid passage.